Test Overview
This test utilizes a G-C rich PCR method with a FAM-labeled gene-specific primer designed to amplify the entire repeat region and a CGG repeat primer designed to anneal and amplify anywhere along the repeat region. Amplification is followed by analysis with capillary electrophoresis (CE). This test is run in conjunction with methylation PCR to determine methylation status of the gene promoter. Results may be confirmed by a second method such as Southern Blotting, if indicated.
Analysis of CGG repeats present in the FMR1 gene in a patient with clinical features consistent with Fragile X Syndrome or determination of the carrier status of a family member.
Normal alleles: 5-44 CGG repeats; Intermediate (gray zone) mutations: 45-54 CGG repeats; Premutations: 55-200 CGG repeats; Full Mutation: >200 CGG repeats. Interpretative report provided.
This assay can detect up to 200 CGG repeats in the FMR1 gene. Samples containing > 200 CGG repeats will be reported as "full mutation (>200 CGG repeats)".
Test Details
21 days
- FRXFAS
- Fragile X Frag Analysis Shadow
- FRXFA
- Fragile X Mutation Detection by Fragment Analysis
- FXPB
- Fragile X Synd Car Det,Blood
- FRAGILE X FRAG ANALYSIS
- Fragile X Syndrome
- x-linked mental retardation
- Fragile X tremor ataxia syndrome
- Fragile X associated premature ovarian insufficiency (FXPOI)
- Autism / Intellectual Disability
Specimen Requirements
Collect specimen in a lavender top tube. Send intact specimen within 24 hours if stored at room temperature or within 5 days if stored refrigerated. Include the patient's family history, pedigree, and ethnicity on the test requisition. Obtaining informed consent from the patient prior to genetic testing is strongly recommended. If desired, a UMHS Request and Consent for Genetic Testing form can be obtained from the MMGL Molecular Genetics Laboratory by contacting the MLabs Client Services Center at 800-862-7284 or online at https://mlabs.umich.edu/sites/default/files/2020-01/file/pci-mmgl_infor….
Additional Information
The American College of Medical Genetics recommends that both a routine karotype (Chromosome Analysis, Blood, Constitutional) AND a molecular test (Fragile X Syndrome Mutation Detection) be performed. By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes medical geneticist interpretation of results billed as a separate additional charge. This test is not available without interpretation.